Medicament infusion devices are utilized to deliver liquid fluid medicine to patients. For example, insulin infusion devices are often used by persons with diabetes to maintain adequate insulin levels throughout the day or to increase insulin levels during mealtime. These insulin infusion devices can replace the syringe-based injections common among those with diabetes.
Insulin infusion devices are available in several forms and include several common components. Generally, an infusion device includes a housing that may be worn on a patient's clothing (a belt, for example) or on the patient himself, and that contains a number of mechanical and electrical components. A reservoir holds the insulin and an electro-mechanical pump mechanism (various types are used) delivers the insulin as needed to the patient. Battery-powered electronics control the pump and ensure that the device is operating properly. Various sensors communicate with the electronics and other components to detect occlusions, sound alarms, measure remaining insulin capacity, etc.
While these devices are useful, they do suffer from several shortcomings. First, the high expense of the devices makes them accessible to fewer people than the diabetic population members who may benefit from their use. Second, failure or malfunction of one component requires repair or replacement of the entire device, a costly scenario. For example, if the pump fails, often the entire unit (including the properly functioning—and expensive—electronics) must be replaced. Third, over time the device gets dirty due to repeated uses, which requires periodic cleaning and may cause a failure condition at a later date. Fourth, the complexity of the devices requires significant battery power to operate pumps, monitor sensors, and send alerts and notifications to a patient. Power and electronic requirements are often so significant as to require large batteries, thus increasing the physical size, weight, and cost of the device. Fifth, in devices which administer a liquid fluid medicine on demand, a full dose may not always be delivered.
It is therefore desirable to ensure the delivery of a single, full dose of medicament with a low-cost, mechanical mechanism in a reliable and safe manner.